With the continuous increase in data center services, users' demands are increasing and the scale and functions of data centers are increasing in size and complexity. Virtualization is commonly employed to make full use of data center resources and meet higher service demands. The virtualization may include hosting virtual machines (VMs) on physical servers. Each of the VMs may operate independently without influencing each other, and have its own operating system, applications and virtual hardware environment.
The VMs may communicate with each other and to the outside world using a virtual switch. The virtual switch may be software running with VM management software to implement switching between VMs and between the VMs and external hosts. The virtual switch may perform Edge Virtual Bridging (EVB), which is an IEEE standard that facilitates the interaction between virtual switching environments and the first layer of the physical switching infrastructure. The virtual switch may be a virtual Ethernet bridge (VEB) which is generally software that acts similar to a layer 2 hardware switch providing inbound/outbound and inter-VM communication. A VEB can aggregate VM traffic as well as provide frame delivery between VMs based on Media Access Protocol (MAC) addresses. Also, the VEB may implement Virtual Edge Port Aggregator (VEPA) standard. The VEPA hands all the network traffic generated by the VM to the physical switch connected to the server hosting the VM for processing. Even the traffic among VMs hosted on the same server is processed on the physical switch and returned to the destination VM on the server. The VEPA realizes traffic forwarding among VMs through the physical switch, and also realizes supervision of the traffic of the VMs.